If you have modified the colors in another workbook you can import from that
workbook into your workbook.
That other workbook must be open.
You can modify the colors at Tools>Options>Colors>Modify.
Note: this is a workbook setting, not a global setting for Excel.
Some people have been known to modify the colors in a blank workbook then save
that blank workbook as a Template named BOOK.xlt which is stored in the XLSTART
folder.
This becomes the default workbook for File>New or CTRL + n or New File Icon.
Gord Dibben MS Excel MVP